Device for forming amalgam fillings



INVENTOR ATTORN IV Patented Oct. 22, 1935 DEVICE FOR FORMING AMALGAMFILLINGS Anders Ejde, Poulsbo, Wash.

Application November 21, 1934, Serial No. 754,139

3 Claims.

This invention relates to a matrix retainer especially adapted for useby dentists to give proper form to amal am fillings and has for theprimary object the provision of a device of the above stated characterwhich may be quickly and conveniently positioned with respect to a toothto be filled and only requires space for the mold element on one side ofthe tooth and provides clear vision to the work and causes the moldelement to readily conform to the tooth and thereby prevent lapover ofthe filling and further prevents the danger of injury to the gums.

With these and other objects in view this invention consists in certainnovel features of construction, combination and arrangement of parts tobe hereinafter more fully described and claimed.

For a complete understanding of my invention, reference is to be had tothe following description and accompanying drawing, in which Figure l isa top plan view illustrating a matrix retainer applied to a tooth andconstructed in accordance with my invention.

Figure 2 is an end elevation illustrating the retainer.

Figure 3 is a sectional view taken on the line 33 of Figure 2.

Figure 4 is a side elevation illustrating the device.

Figure 5 is a transverse sectional view taken on the line 55 of Figure4.

Figure 6 is a plan view illustrating the mold element.

Referring in detail to the drawing, the numeral I indicates a channeledbar provided at its offset end with apertured ears 2 arranged at rightangles to the bar to form journals for the ends of a feed shaft 3. Afeed nut 4 in the form of a block is threaded on the feed shaft 3 andhas an offset portion 5 engaging in the channeled bar to retain theblock against rotation with the shaft so that on rotation of the shaftthrough the manipulation of a finger piece 6 the block will be caused toslide from one end of the bar to the other end. Opposite walls or facesof the block have formed thereon lugs I either one of which is adaptedto fit an opening 8 of a mold element 9. The mold element is ofelongated formation having an opening 8 adjacent each end and ispreferably constructed of a flexible metallic material.

A frame member it) is fixed to the bar I intermediate the latters endsand extends transversely of the bar and consists of relatively spacedteeth I I cooperating with each other in defining substantially U-shapedspaces to accommodate a tooth, as shown in Figure 1.- The end teeth ofthe frame member l6 have formed thereon lugs I2 either of which isadapted to enter one of the openings 8 of the mold member.

The device is positioned as shown in Figure 1 relative to a tooth to befilled and with one end of the mold member fastened to one of the lugsof the block and the other end fastened to one of the lugs I2, said moldmember will be caused to adjust itself to the tooth overlying theamalgam filling. A device of this character obviates the use of thecustomary band now employed and which encircles the tooth having thecavity requiring the necessity of forcing the band between the tooth andthe tooth adjacent thereto, which practice frequently injures the gumbetween the teeth. It is to be noted that this device avoids thenecessity of forcing the teeth apart and only requires space for themold element on one side of the tooth having the cavity and further thatthe device can be quickly and conveniently placed in position andadjusted and when adjusted causes the mold element to conform to theshape of the tooth and thereby prevent lapover of the filling.

The device herein described will work successfully on upper and lowerright and left bicuspids and molars in connection with mesial occlusaland distal occlusal cavities.

Having described the invention, I claim:

1. A matrix retainer comprising a bar, a frame element fixed to said barand arranged transversely thereof and provided with a tooth receivingnotch, a flexible mold element removably secured to either end of saidframe element, and means adjustably mounted to the bar and having themold element adjustably connected thereto.

2. A matrix retainer comprising a bar, a frame element carried by saidbar and arranged transversely thereof, a flexible mold element removablysecured to either end of said frame element, means adjustably mounted tothe bar and having the mold element adjustably connected thereto, saidframe element having relatively spaced teeth defining therefromsubstantially U-shaped spaces.

3. A matrix retainer comprising a channeled bar, a feed shaft journaledto said bar, a finger piece for said shaft, a feed nut mounted to theshaft and having an offset fitting in the channeled bar, a frame elementcarried by and arranged transversely of said bar and positionedintermediate the ends of the latter, lugs formed on opposite faces ofthe nut and at opposite ends of the frame member, a flexible moldelement having openings to permit application of said mold element tolugs of the nut and frame member, said frame element having relativelyspaced teeth to define substantially U-shaped spaces for accommodating atooth to be filled.

ANDERS EJDE.

